Prognosis of Tandem Occlusions versus Isolated Intracranial Occlusions

Both acute single intracranial and tandem occlusions are managed with intravascular thrombectomy with success, but little evidence exists about the differences in their mid-term outcome. We aim to compare the outcome at 3 months after tandem (extracranial internal carotid and/or middle cerebral artery) and single intracranial (M1 division) occlusions, and to identify the factors, which determine such prognosis.

A total of 66 patients (33 with tandem and 33 with singleM1 occlusions) who underwent emergent intravascular therapy in our center between November of 2013 and November of 2016 were collected. Patients' medical histories were reviewed for clinical and radiological variables. A modified Rankin Scale of 3 or more was considered as bad outcome. An interobserver concordance analysis evaluated the quality of collaterals in the initial computed tomography through the Maas, Miteff, and CGS (collateral grading scale) scales.

No differences were found in theprognosis of tandem versus single M1 occlusions (P = .30). The kappa index for the Maas scale was .77 (95% confidence interval [CI] .59-.94) and bad collaterals were defined by a score of 1 or 2. The factors independently associated with a worse prognosis were the presence of bad collaterals (adjusted odds ratio [OR] 6.03, 95% CI 1.01-35.9, P = .048) and an incomplete revascularization (adjusted OR 6.01, 95% CI 1.01-35.7, p = .049).

The outcome of patients with acute stroke secondary to tandem or M1 occlusions has not been found to depend on their localization. The bad quality of collaterals is the main factor related to an unfavorable prognosis.